Help with a K4900

jbk

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Donor 4 years: 2011, 2013-2015
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rivesville, West Virginia
My K4900 is having issues. I just installed a BR Cap Kit, reflowed all the connector pins and pots. The problem is the Horz hold. the picture rolls constantly and with very micro-adjustments I can get it almost stopped but there is a curve to the picture. I suspect a bad/old/dirty pot at the Horz Hold. Is this a plausable diagnosis and if so what is the value of this pot? Any help would be great.
 
It could be the pot, and it could also still be that the horizontal sync isn't connecting to the board... maybe try connecting a meter to the wire at the jamma harness, and measure onto the first contact point PAST the connector on the gameboard to make sure the signal is getting through (test for a short in the wire, which you should have).
 
I'll Have to check it tomorrow. It is in a Qbert. What kind of reading should be coming through the white sync wire?
 
Started tracing the H Sync from the monitor to the MPU. Found a broken solder joint on one of the connectors on the filter board. Qbert lives again. Now I have to clean and do cosmetic stuff, rebuild the PS and update the battery on the MPU.
 

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